This invention relates to the use of a dry predust comprising an effective amount of a hydroxypropylmethyl cellulose derivative and the improved freeze/thaw stability provided to breaded and non-breaded convenience foodstuffs which are coated with the predust prior to the application of an aqueous batter mix, pre-fried, frozen, and ultimately cooked in a microwave oven.
Batter coated fried foods have a broad appeal. Among the most popular batter coated foods are fried chicken and fish as well as other meat products, however, a wide variety of other foods, such as vegetables, and even fruits can be coated and then cooked by frying. Deep-fried food batters, whether for use with fresh or frozen foods, consist primarily of farinaceous materials such as starches and/or flours along with other optional ingredients such as egg solids, baking powder, cream of tartar, preservatives, seasonings, coloring matter and milk solids. These mixtures are combined with water so as to obtain a desired coating viscosity whereupon they are applied to the food ordinarily by means of a dip, spray or cascade technique. Before frying, the batter coated food may be coated with a breading such as corn meal, cracker crumbs, bread crumbs or the like if so desired.
Prior to batter application, a foodpiece often will undergo a predusting step. Predusting has primarily been performed in order to create a surface which is more conducive to the physical adhesion of a wet batter. Applying a predust has always been a challenge in the coating industry because of the need to apply a thin, uniform layer. Where absent, the batter will not adhere evenly to the foodpiece. Similarly, the batter is unable to hydrate large lumps of the predust resulting in batter film break away causing voids in these areas.
Typical predust materials have included farinaceous-based materials such as very fine cereal flour, a flour combination, starch or the dry batter itself.
In order to obtain a fried product, a batter-coated food piece must be cooked in the presence of frying oils or melted fat at elevated temperatures. Foods thus prepared may be immediately consumed or may be packaged and quick frozen so that the ultimate consumer may prepare the foodstuff merely by reheating. In many cases, the food may only receive a partial cooking or "pre-frying" at this point, whereupon it is packaged and quick frozen with the cooking of the pre-fried frozen foodstuff completed at a later time by the consumer.
A growing trend to spend less time on food preparation has lead to a great demand for time-saving "ready-to-heat" frozen food products now on the market. The wide use of microwave ovens, now a standard feature in many homes and restaurants, has further led to the reduction in cooking time spent by consumers. Many products cooked by means of microwaving or baking are indistinguishable from each other. Unfortunately, frozen pre-fried foodstuffs have shown strong differences when comparisons are made between final products which have been fried, baked and most particularly microwaved. Microwaved pre-fried products have tended to be undesirably soggy, and as such have not been recommended for microwaving.
It had generally been accepted that frozen pre-fried products which were subsequently cooked by microwave radiation would be inferior in crispness to those products cooked in an oven. There are at least two reasons for which the inferiority of the microwaved products has been attributed.
Firstly, the transfer of heat to a food piece during frying or baking is opposite that for microwaving. Microwave radiation cooks food pieces by heating the water contained therein which in turn acts to cook the entire piece. For this reason, it is often explained that microwave radiation cooks products from the interior outwards, resulting in the coating of a pre-fried piece being the last part to be cooked. During microwaving, the moisture in the food piece is driven outwards towards the surface, which can cause the food piece to become soggy. During frying or baking, on the other hand, the outer coating receives the most exposure to cooking temperatures while the interior receives the least, thus providing a crispy outer coating.
Secondly, food pieces which are cooked in the presence of hot fat or oil by frying are usually cooked at temperatures of at least 350.degree. F. (176.degree. C.) to about 425.degree. F. (218.degree. C.) preferably 375.degree.-395.degree. F. (190.degree.-202.degree. C.) which are sufficiently high to fry the food piece. It is recommended that pre-fried food pieces be oven baked at comparable frying temperatures so that residual oil, contained on the surface of all pre-fried foods, will continue to cook the food piece. Microwave ovens, on the other hand, are limited to cooking temperatures such that the residual oil retained on a food piece after pre-frying will not continue to cook the piece.
In addition to crispness, another desirable property of a microwaved pre-fried product is an undifferentiable interface between the batter coating and the food piece. The crispness of a food piece becomes overshadowed as the interface worsens by going from thin and dry to floury, bready and finally to pasty. Weepage is also an important concern. Fluid migration during freezing or microwaving due to gravity may result in the pooling of some fluid on the underface of the product resulting in a product which is soggy beneath a crispy coating.
U.S. Pat. Nos. 4,529,607 and 4,595,597 (issued on July 16, 1985 and June 17, 1986 respectively to J. Lenchin et. al.) disclose a batter mix formulation for coating pre-fried microwavable foodstuffs. The batter mix, which advantageously employs about 50 to 80% of a high amylose flour, based on batter mix solids, provides a crispy pre-fried foodstuff which remains crispy after freezing and subsequent subjection to microwave cooking. The disclosures of the above references are hereby incorporated herein by reference.
Most frozen pre-fried, convenience food products are produced and packaged to have an optimum shelf life of about three months. During this time period, it is not uncommon for storage temperatures to fluctuate causing the frozen products to undergo one or more partial or complete freeze/thaw cycles during transportation and storage. Due to the deleterious effect repeated freezing and thawing cycles has on a frozen pre-fried foodpiece causing a significant exudation of moisture therefrom, the freeze/thaw stability of a product is a serious concern in the frozen food industry.
Freeze/thaw stability of a pre-fried foodpiece is especially important for products ultimately reconstituted by microwave cooking. As discussed above, the high cooking temperatures of oven reconstitution enables a significant amount of moisture present on the exterior of a foodpiece which could result in a soggy product to be removed. Microwave cooking, on the other hand, is conducted at a temperature which does not allow for easy removal of excess water pooled on the underface of the product.
Frozen pre-fried chicken pieces prepared employing a conventional predust and the batter mix of J. Lenchin et al. (described above) are unable to withstand one freeze/thaw cycle with the pre-fried coating exhibiting a poor interface with severe weepage.
There is therefore a need in the convenience food industry for a method of providing freeze/thaw stable microwavable pre-fried foodstuffs. The ability to provide a microwaveable pre-fried chicken piece which is able to withstand three freeze/thaw cycles would be recognized in the convenience food industry as a significant improvement.
Accordingly, it is an object of the present invention to provide a dry predust which is capable of improving the shelf-stability of a microwaveable pre-fried foodstuff.
It is further an object to provide a method for preparing a microwaveable pre-fried foodstuff which is capable of withstanding repeated freeze/thaw cycles.